title: Abnormal P600 word repetition effect in elderly persons with preclinical Alzheimer's disease.
abstract: We sought cognitive event-related potential (ERP) biomarkers of "Preclinical Alzheimer's disease" (Pre-AD) using an incidental verbal learning paradigm with high sensitivity to prodromal AD. Seven elderly persons, with normal cognition at the time of ERP recordings, but who showed subsequent cognitive decline or AD pathology at autopsy (n = 5, mean Braak stage = 2.8), were compared to 12 "robust" normal elderly (RNE) persons who remained cognitively normal (Mfollow-up = 9.0 years). EEG was recorded during a word repetition paradigm (semantically congruous (50%) and incongruous target words repeat ~10-140 seconds later). The RNE P600 congruous word repetition ERP effects (New minus Old congruous words) were significantly larger than in Pre-AD (mean amplitudes = 3.28 vs. 0.10 μV, p = .04). High group discrimination (84%) was achieved (by a P600 amplitude cutoff of ~1.5 μV). Abnormal P600 word repetition effects in cognitively normal elderly persons may be an important sign of synaptic dysfunction and Preclinical AD.
authors.affiliation: a Department of Neurology , University of California , Davis , CA , USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Olichney
authors.forename: Jamie
authors.initials: J
authors.lastname: Pak
authors.forename: David P
authors.initials: DP
authors.lastname: Salmon
authors.forename: Jin-Chen
authors.initials: JC
authors.lastname: Yang
authors.forename: Tim
authors.initials: T
authors.lastname: Gahagan
authors.forename: Ralph
authors.initials: R
authors.lastname: Nowacki
authors.forename: Lawrence
authors.initials: L
authors.lastname: Hansen
authors.forename: Douglas
authors.initials: D
authors.lastname: Galasko
authors.forename: Marta
authors.initials: M
authors.lastname: Kutas
authors.forename: Vicente J
authors.initials: VJ
authors.lastname: Iragui-Madoz
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000503:physiopathology; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000175:diagnosis* / Q000503:physiopathology; D004192:Discrimination, Psychological / Q000502:physiology; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D060865:Repetition Priming / Q000502:physiology; D012189:Retrospective Studies; D014706:Verbal Learning / Q000502:physiology*; D014825:Vocabulary